JPH0513544A - Semiconductor manufacturing device with vacuum chamber - Google Patents

Abstract

PURPOSE:To eliminate the calibration error due to removal or carrying of capacitance manometer by calibrating the capacitance manometer while operating a high vacuum equipment for calibration in such a state that the first valve is closed and the second valve opened, respectively. CONSTITUTION:In order to calibrate a capacitance manometer 8, a chamber isolation valve 4 and capacitance manometer isolation valve 6 are closed, a calibration valve 9 and turbo-pump isolation valve 12 are opened, and a turbo pump 10 is activated and at the same time an ionization gage 11 is operated to measure the degree of vacuum. When the degree of vacuum lowers below the minimum detection pressure of the manometer 8, the zero-point of the capacitance manometer is adjusted. Thus, the capacitance manometer can be calibrated without removing it from the manufacturing equipment because the pressure exerted on the capacitance manometer can be lowered below its minimum detection pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, particularly a vacuum evacuation facility for a process, a vacuum chamber connected to the process vacuum evacuation facility for processing a semiconductor wafer therein, and an inside of the vacuum chamber. The present invention relates to a semiconductor manufacturing apparatus having a capacitance manometer for measuring pressure.

[0002]

2. Description of the Related Art Generally, in a semiconductor manufacturing apparatus having a vacuum chamber, it is necessary to monitor the pressure in the vacuum chamber, but a capacitance manometer is often used for this pressure monitor. The pressure in the vacuum chamber measured by this capacitance manometer is usually managed as a process vacuum degree and is an important process parameter.

The above-described capacitance manometer is prone to drift of the zero point with time and a deviation of the indicated value due to a sudden pressure change. Therefore, in order to maintain stable serial data process conditions and improve the yield of semiconductor manufacturing. It requires frequent calibration work.

The calibration of the capacitance manometer includes offset adjustment and linearity adjustment.
Normally, there is not much variation in linearity adjustment, and since it is difficult for the user to make adjustments, only offset adjustment is performed as routine work. As a method for adjusting the offset of the capacitance manometer, the minimum detection pressure of the capacitance manometer (usually 1 × 10
^A pressure lower than ^-4 Torr) is applied so that the capacitance manometer indicates 0 V at that time.

In a semiconductor manufacturing apparatus having a high vacuum exhaust equipment such as a turbo pump, a cryopump, and a diffusion pump as a vacuum exhaust system of a vacuum chamber, the high vacuum exhaust equipment is operated to adjust the pressure of the vacuum chamber to a capacitance manometer. Can be set to a value lower than the lowest detected pressure of 1. However, in a semiconductor manufacturing apparatus without such a high vacuum exhaust facility, the pressure in the vacuum chamber cannot be lower than 1 × 10 ⁻⁴ Torr. Therefore, the capacitance manometer is removed from the manufacturing apparatus, attached to a separately provided high vacuum chamber for calibration, calibration work is performed, and after calibration, it is attached again to the vacuum chamber of the manufacturing apparatus.

[0006]

In the conventional method of calibrating a capacitance manometer, the capacitance manometer is detached from the vacuum chamber, calibrated, and then mounted in the vacuum chamber as described above. is there. (1) Since the indicated value of the capacitance manometer changes according to the change of pressure, the inside of the capacitance manometer must be maintained in a vacuum state when it is carried between the calibration vacuum chamber and the vacuum chamber of the manufacturing apparatus. Is extremely troublesome. (2) Since the indicated value of the capacitance manometer fluctuates depending on the mounting posture, the capacitance manometer must be mounted in the vacuum chamber for calibration in the same posture as when it is mounted in the manufacturing device during calibration, which is troublesome and causes an error in the mounting posture. Calibration error due to is inevitable. (3) It is necessary to install an expensive calibration device, that is, a high-vacuum chamber having a high-vacuum exhaust facility, only for calibrating the capacitance manometer. (4) The number of steps for calibration is large, which makes the work troublesome and, in combination with the drawback of (3), increases the running cost.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned drawbacks, the present invention provides a process vacuum evacuation facility and a vacuum chamber connected to the process vacuum evacuation facility for internally processing a semiconductor wafer, First in this vacuum chamber
And a capacitance manometer for measuring the internal pressure of the capacitance manometer, and a capacitance manometer connected to the capacitance manometer via a second valve so that the pressure acting on the capacitance manometer is lower than the minimum detection pressure of the capacitance manometer. A high vacuum exhaust facility for calibration capable of maintaining a pressure, the first valve is closed, the second valve is opened, and the high vacuum exhaust facility for calibration is operated to calibrate the capacitance manometer. It is characterized by being configured as described above.

The present invention is further intended to provide a semiconductor manufacturing apparatus in which the above-described capacitance manometer is automatically calibrated, and is connected to a process vacuum evacuation facility and the process vacuum evacuation facility. Is
A vacuum chamber for internally processing the semiconductor wafer is connected to the vacuum chamber via a first electromagnetic valve, and a capacitance manometer for measuring the internal pressure thereof is connected to the capacitance manometer via a second electromagnetic valve. A calibration high vacuum exhaust facility capable of maintaining a pressure acting on the capacitance manometer at a pressure lower than the minimum detection pressure of the capacitance manometer, and a minimum capacitance of the capacitance manometer connected to the calibration high vacuum exhaust facility. A high vacuum gauge capable of detecting a pressure lower than the detected pressure, and at a predetermined timing, the first electromagnetic valve is closed and the second electromagnetic valve is opened to operate the high vacuum exhaust equipment for calibration. A calibration operation of the capacitance manometer is automatically started, and a predetermined operation is performed by the high vacuum gauge. After having reached the degree of vacuum is detected, it is characterized in that it comprises a control means for calibration of the capacitance manometer automatically.

[0009]

According to the semiconductor manufacturing apparatus of the present invention, when the capacitance manometer is calibrated, the pressure acting on the capacitance manometer is set to the minimum detected pressure by operating the high vacuum exhaust equipment for calibration incorporated in the semiconductor manufacturing apparatus. Lower pressures allow calibration to be performed without removing the capacitance manometer from the manufacturing equipment. Therefore, it is possible to eliminate the fluctuation of the indication value due to the removal and carrying of the capacitance manometer, and also to eliminate the calibration error based on the error of the mounting posture. In addition, at the time of calibration, only the mounting part of the capacitance manometer and the inside of the capacitance manometer need to have a high vacuum, so it is not necessary to provide a large and expensive high vacuum exhaust facility, and the required high vacuum degree can be reached in a short time. The calibration time can be greatly shortened in combination with the need for removing the capacitance manometer. Further, as the auxiliary exhaust equipment of the high vacuum exhaust equipment, that of the semiconductor manufacturing apparatus can be used, and in that case, the equipment cost can be reduced.

Further, in the second invention, the capacitance manometer can be automatically calibrated at an arbitrary timing. For example, the capacitance manometer can be automatically calibrated every time the semiconductor wafer is changed, the lot is changed, or when the calibration start switch is provided and operated, and the process pressure can be controlled reliably and easily. Can be performed, and the yield can be further improved.

[0011]

FIG. 1 is a block diagram showing the overall construction of an embodiment of a semiconductor manufacturing apparatus according to the present invention. In this embodiment, an apparatus for dry etching an oxide film formed on a wafer is taken as an example. Of course, the invention can be applied to devices that perform other processes. Vacuum chamber 1
A semiconductor wafer is carried in by an auto loader (not shown), and is discharged by an auto unloader after etching. Further, the vacuum chamber 1 is configured to be selectively supplied with process gas such as CF ₄ and CHF ₃ via a pipe 2.

The vacuum chamber 1 is connected to a vacuum pump 5 via a conductance valve 3 and a chamber isolation valve 4, and this vacuum pump is operated to reduce the pressure inside the vacuum chamber to a pressure of about 5 × 10 ^-3. be able to. The vacuum chamber 1 further connects a capacitance manometer 8 via a capacitance manometer isolation valve (first valve) 6 and a T-shaped pipe 7. The T-shaped pipe 7 is further connected to a turbo pump 10 via a calibration valve (second valve) 9. Further, an ionization vacuum gauge 11 is provided between the calibration valve 9 and the turbo pump 10 so that the high vacuum degree by the turbo pump can be measured. The turbo pump 10 is further connected to the vacuum pump 5 via a turbo pump isolation valve 12.

When performing the normal process, the calibration valve 9 and the turbo pump isolation valve 12 are used.
Keep it closed. The wafer is carried into the vacuum chamber 1, and the inside of the vacuum chamber is decompressed by the vacuum pump 5. The pressure inside the vacuum chamber 1 is measured by the capacitance manometer 8, and after reaching the ultimate vacuum of 5 × 10 ⁻³ Torr, the process gas is introduced through the pipe 2. During this period, the conductance valve 3 is adjusted to control the pressure in the vacuum chamber to a pressure of about 3 × 10 ^-1 Torr. This pressure adjustment takes place automatically as usual, for which purpose the output signal of the capacitance manometer 8 is supplied to the control circuit 13. When the pressure in the vacuum chamber 1 reaches a preset prescribed pressure, high-frequency power is applied to generate plasma in the vacuum chamber 1, and the oxide film formed on the wafer surface is dry-etched.

When the capacitance manometer 8 is calibrated, the chamber isolation valve 4 and the capacitance manometer isolation valve 6 are closed, the calibration valve 9 and the turbo pump isolation valve 12 are opened, the turbo pump is started and the ionization is performed. The vacuum gauge 11 is operated to measure the degree of vacuum. When the vacuum degree measured by the ionization vacuum gauge 11 becomes lower than 1 × 10 ⁻⁴ Torr which is the minimum detection pressure of the capacitance manometer 8, the zero point of the capacitance manometer is adjusted.
That is, at this time, the voltage output from the capacitance manometer 8 is adjusted to be 0V.

If the capacitance manometer is to be calibrated by setting the pressure in the vacuum chamber to be lower than the minimum detection pressure of the capacitance manometer 8, assuming that the volume of the vacuum chamber 1 is 50 liters, it is about 200 liters / sec. A large turbo pump having an evacuation speed is required. However, in the present invention, the portion to be evacuated by the turbo pump is only the inside of the T-shaped pipe 7 and the capacitance manometer 8, so the volume is at most about 1 liter. Therefore, a small turbo pump of about 30 l / sec is sufficient.

FIG. 2 is a block diagram showing the configuration of another embodiment of the semiconductor manufacturing apparatus according to the present invention. The same parts as those shown in FIG. 1 are designated by the same reference numerals and their description is omitted. In this example, the capacitance manometer 8 is automatically calibrated. That is, the output signal of the ionization vacuum gauge 11 is supplied to the zero point calibration circuit 21,
The calibration signal output from the zero point calibration circuit is supplied to the capacitance manometer 8. The output signal of the capacitance manometer 8 is supplied to the comparison circuit 22 and also connected to the control circuit 23, and the output signal of the comparison circuit is also supplied to the control circuit. The valves 3, 4, 6, 9 and 12 are electromagnetic valves, and these electromagnetic valves are controlled by the control circuit 23, and the opening of the conductance valve 3 is adjusted by the control circuit as in the previous example. Further, the control circuit 23 is also configured to control the operations of the ionization vacuum gauge 11 and the turbo pump 10. A mode selection switch 24 is further connected to the control circuit 23. This mode selection switch 2
The switch 4 is provided with a switch for designating the timing for calibrating the capacitance manometer 8. That is, the mode selection switch 24 includes a switch 24a for calibrating the capacitance manometer 8 every time the semiconductor wafer is replaced.
And a switch 24b for calibrating the capacitance manometer every time the rod of the semiconductor wafer is replaced, and a switch 24c for calibrating the capacitance manometer at an arbitrary timing.

Now, the switch 2 of the mode selection switch 24
4a is driven and a mode for calibrating the capacitance manometer 8 for each wafer is selected. When the processing of the wafer is completed from the computer controlling the process in the vacuum chamber 1 and the signal indicating that the wafer is discharged from the vacuum chamber is supplied to the control circuit 23, the control circuit closes the valves 4 and 6, Open valves 9 and 12. In this state, the inside of the turbo pump 10 is evacuated. The control circuit 23 sends a signal to the turbo pump 10 to drive it after a lapse of 10 to 20 seconds predetermined by the timer. When the number of revolutions of the turbo pump 10 reaches a predetermined value, the control circuit 23 sends a signal to the ionization vacuum gauge 11 to activate it.

The T-shaped pipe 7 is driven by the turbo pump 10.
The inside of the is decompressed, but this pressure is
And the measured value is sent to the control circuit 23. When the control circuit 23 detects that the vacuum degree measured by the ionization vacuum gauge 11 is lower than 1 × 10 ⁻⁴ Torr,
The control circuit sends a calibration start signal to the zero point calibration circuit 21 to start zero point calibration of the capacitance manometer 8.

At this time, the output signal from the capacitance manometer 8 is supplied to the comparator 22 where it is compared with the reference voltage of 0V. After confirming by the output of the comparator 22 that the output voltage of the capacitance manometer 8 has become 0 V, the control circuit 23 starts the operation of ending the calibration operation, and stops the operation of the turbo pump 10 and the ionization vacuum gauge 11, Close 9 and 12 and open valves 4 and 6.

The switch 24b of the mode selection switch 24
Is closed, the calibration start signal is sent from the process computer to the control circuit 23 when the wafer rod is switched.
The calibration operation described above is automatically performed. When the switch 24c is closed, the calibration start signal is supplied from the process computer to the control circuit 23 when the processing of the wafer is completed, and the above calibration operation is automatically performed.

The present invention is not limited to the above-mentioned embodiments, but various modifications are possible. In the above-described embodiment, the capacitance manometer for measuring the pressure in the vacuum chamber for dry etching the oxide film formed on the semiconductor wafer is calibrated, but the pressure in the vacuum chamber for performing any other process is measured. The capacitance manometer can be calibrated. Further, in the above-mentioned embodiment, the turbo pump is used to make the pressure lower than the minimum detection pressure of the capacitance manometer at the time of calibration, but a high vacuum exhaust equipment such as a cryopump and a diffusion pump may be used.

[0022]

As described above, according to the semiconductor manufacturing apparatus of the present invention, the capacitance manometer for measuring the pressure in the vacuum chamber can be calibrated without removing the capacitance manometer from the manufacturing apparatus. The calibration error can be eliminated by removing or carrying the manometer, and the calibration work becomes very easy. In particular, in order to apply a high vacuum to the capacitance manometer as in the above-described embodiment, when the auxiliary exhaust equipment is added to the existing vacuum exhaust system, the equipment for calibration becomes small and the equipment cost becomes low. . Further, in the invention in which the calibration is automatically performed, the calibration work is further simplified, human error is eliminated, process control can be performed reliably and accurately, and the yield of semiconductor manufacturing can be improved. .

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of a semiconductor manufacturing apparatus according to the present invention.

FIG. 2 is a block diagram showing an overall configuration of another embodiment of the semiconductor manufacturing apparatus according to the present invention.

[Explanation of symbols]

1 vacuum chamber 3 conductance valve 4 pump isolation valve 5 vacuum pump 6 capacitance manometer isolation valve (first valve) 8 capacitance manometer 9 configuration valve (second valve) 10 turbo pump 11 ionization vacuum gauge 12 turbo pump isolation valve 21 Zero point calibration circuit 22 Comparator 23 Control circuit 24 Mode selection switch

Claims (2)

[Claims] 1. A process vacuum evacuation facility, a vacuum chamber connected to the process vacuum evacuation system for processing a semiconductor wafer therein, and a vacuum chamber connected to the vacuum chamber via a first valve, and the inside thereof. A capacitance manometer for measuring pressure, and a calibration high pressure connected to the capacitance manometer via a second valve and capable of maintaining the pressure acting on the capacitance manometer at a pressure lower than the minimum detection pressure of the capacitance manometer. A vacuum chamber, wherein the first valve is closed and the second valve is opened, and the high vacuum exhaust equipment for calibration is operated to calibrate the capacitance manometer. A semiconductor manufacturing apparatus having. 2. A process vacuum evacuation facility, a vacuum chamber connected to the process vacuum evacuation system for internally processing a semiconductor wafer, and a vacuum chamber connected to the vacuum chamber via a first electromagnetic valve, A capacitance manometer for measuring an internal pressure, and a calibration connected to the capacitance manometer via a second electromagnetic valve and capable of maintaining a pressure acting on the capacitance manometer at a pressure lower than a minimum detection pressure of the capacitance manometer. High vacuum exhaust equipment, a high vacuum gauge connected to the calibration high vacuum exhaust equipment and capable of detecting a pressure lower than the minimum detection pressure of the capacitance manometer, and the first electromagnetic valve at a predetermined timing. Closed, the second solenoid valve opened, and the high vacuum exhaust equipment for calibration was operated. Control means for automatically starting the calibration operation of the capacitance manometer and automatically calibrating the capacitance manometer after it is detected that a predetermined high vacuum level has been reached by the high vacuum gauge. A semiconductor manufacturing apparatus having a vacuum chamber.